The objective of this research is to isolate and characterize the phospholipid exchange proteins in lung. The purified proteins will be used to study the specificity for different phospholipids and the role of the acceptor in the exchange process. The protein will be purified from the supernatant of a lung homogenate following ultracentrifugation. The supernatant will be acidified to 5.1 and centrifuged to provide starting material. This fraction will be precipitated with ammonium sulfate, and subjected to gel filtration, electrofocusing, ion exchange columns, and polyacrylamide gel electrophoresis. Purified proteins will be used to study exchange between artificial vesicles and specific membranes, particularly the lamellar bodies. Specificity for exchange of phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol will be determined for each purified fraction with exchange activity. The overall goal is to provide information for a better understanding of biological membrane biogenesis, structure, and function.